NH_(3) in ambient air directly leads to an increase in the aerosol content in the air. These substances lead to the formation of haze to various environmental problems after atmospheric circulation and diffusion. Cont...NH_(3) in ambient air directly leads to an increase in the aerosol content in the air. These substances lead to the formation of haze to various environmental problems after atmospheric circulation and diffusion. Controlling NH_(3) emissions caused by ammonia escaping from mobile and industrial sources can effectively reduce the NH_(3) content in ambient air. Among the various NH_(3) removal methods, the selective catalytic oxygen method (NH_(3)-SCO) is committed to oxidizing NH_(3) to environmentally harmless H_(2)O and N_(2);therefore, it is the most valuable and ideal ammonia removal method. In this review, the characteristics of loaded and core-shell catalysts in NH_(3)-SCO have been reviewed in the context of catalyst structure-activity relationships, and the H_(2)O resistance and SO2 resistance of the catalysts are discussed in the context of practical application conditions. Then the effects of the valence state of the active center, oxygen species on the catalyst surface, dispersion of the active center and acidic sites on the catalyst performance are discussed comprehensively. Finally, the shortcomings of the existing catalysts are summarized and the catalyst development is discussed based on the existing studies.展开更多
Developing bimetallic catalysts is an effective strategy for enhancing the activity and selectivity of electrochemical CO_(2) reduction reactions,where understanding the structure-activity relationship is essential fo...Developing bimetallic catalysts is an effective strategy for enhancing the activity and selectivity of electrochemical CO_(2) reduction reactions,where understanding the structure-activity relationship is essential for catalyst design.Herein,we prepared two Cu-Ag bimetallic catalysts with Ag nanoparticles attached to the top or the bottom of Cu nanowires.When tested in a flow cell,the Cu-Ag catalyst with Ag nanoparticles on the bottom achieved a faradaic efficiency of 54%for ethylene production,much higher than the catalyst with Ag nanoparticles on the top.The catalysts were further studied in the H-cell and zero-gap MEA cell.It was found that placing the two metals in the intensified reaction zone is crucial to triggering the tandem reaction of bimetallic catalysts.Our work elucidates the structure-activity relationship of bimetallic catalysts for CO_(2) reduction and demonstrates the importance of considering both catalyst structures and cell characteristics to achieve high activity and selectivity.展开更多
Density functional theory （DFT） was used to calculate molecular descriptors （properties） for 12 fluoro-quinolone with anti-S.pneumoniae activity. Principal component analysis （PCA） and hierarchical cluster analy...Density functional theory （DFT） was used to calculate molecular descriptors （properties） for 12 fluoro-quinolone with anti-S.pneumoniae activity. Principal component analysis （PCA） and hierarchical cluster analysis （HCA） were employed to reduce dimensionality and investigate in which variables should be more effective for classifying fluoroquinolones according to their degree of an-S.pneumoniae activity. The PCA results showed that the variables ELUMO, Q3, Q5, QA, logP, MR, VOL and △EHL of these compounds were responsible for the anti-S.pneumoniae activity. The HCA results were similar to those obtained with PCA.The methodologies of PCA and HCA provide a reliable rule for classifying new fluoroquinolones with antiS.pneumoniae activity. By using the chemometric results, 6 synthetic compounds were analyzed through the PCA and HCA and two of them are proposed as active molecules with anti-S.pneumoniae, which is consistent with the results of clinic experiments.展开更多
Taking the six common anthocyanidins in nature, i.e. cyanidin, delphinidin, malvidin, pelargonidin, peonidin and petunidin, as examples, this paper summarized the main achievements about the structure-activity relatio...Taking the six common anthocyanidins in nature, i.e. cyanidin, delphinidin, malvidin, pelargonidin, peonidin and petunidin, as examples, this paper summarized the main achievements about the structure-activity relationships of the coloration and stability of anthocyanidins. The coloration and stability of anthocyanidins are funda- mentally determined by the chemical and spatial structures of the anthocyanidins. The electron-deficient state, hydroxylation and methylation patterns, especially the ones on the B-ring, and coplanarity of the three rings of anthocyanidins are inde- pendently or synergetically, positively and/or negatively, influence the coloration and stability of the anthocyanidins. Thereinto, the in vivo colorations of anthocyanins are also related to the organ-selective and crystal- or anthocyanic vacuolar inclusion- related existence of the anthocyanidins. This review could provide a reference for the researches of the structure-optimizing and function-exploiting of anthocyanidins and also for the selection of the crops and cultivars containing specific anthocyani- din profiles.展开更多
Methicillin-resistant Staphylococcus aureus (MRSA), the most common pathogen in hospital and community environments, can cause serious and even fatal infections. The antibiotics currently used for clinical treatment o...Methicillin-resistant Staphylococcus aureus (MRSA), the most common pathogen in hospital and community environments, can cause serious and even fatal infections. The antibiotics currently used for clinical treatment of MRSA have developed resistance, and there is an urgent need to develop new antimicrobials to treat infections caused by MRSA strains. Quinoline analogues play an important role in the development of antimicrobials. Herein, we discussed the current development of antibacterial activities of quinoline analogues, mainly for anti-MRSA activity, and their structure-activity relationships (SARs) from the perspective of using the quinoline nucleus to search for novel potential anti-MRSA candidates. Additionally, the mechanisms of some representative quinoline analogues against MRSA were clarified. Altogether, this review could provide further insights for the rational development of quinoline-based antibacterial drugs, especially against MRSA.展开更多
In searching for effective anticonvulsant agents,fourteen 6-aryl-4.5-di- hydro-3(2H)pyridazinones.fifteen 6-aryl-3(2H)pyridazinones,and seventeen 3-GABA derivatives of 6-aryIpyridazines have been synthesized,and evalu...In searching for effective anticonvulsant agents,fourteen 6-aryl-4.5-di- hydro-3(2H)pyridazinones.fifteen 6-aryl-3(2H)pyridazinones,and seventeen 3-GABA derivatives of 6-aryIpyridazines have been synthesized,and evaluated in mice for the ability to antagonize maximal electroshock seizure(MES).The ED_(50) values showed that 6-(2′,4′- dichlorophenyt)-3(2H)pyridazinone was the most potent anticonvulsant among these corn- pounds(ED_(50)=10.15 mg/kg).The structure-activity relationships of the aryl pyridazinones were studied.The result showed that:(1)the higher the value of the hydrophobic parameter л of the substituent on the phenyl ring.the more potent the anticonvulsant activity of the corn- pound.and(2)only the compounds with an electron withdrawing substituent on the phenyl ring exhibited appreciable anticonvulsant activity.展开更多
Due to the large number of ionic liquids （ILs） and their potential environmental risk, assessing the toxicity of ILs by ecotoxicological experiment only is insufficient. Quantitative structure- activity relationship...Due to the large number of ionic liquids （ILs） and their potential environmental risk, assessing the toxicity of ILs by ecotoxicological experiment only is insufficient. Quantitative structure- activity relationship （QSAR） has been proven to be a quick and effective method to estimate the viscosity, melting points, and even toxicity of ILs. In this work, the LC50 values of 30 imidazolium-based ILs were determined with Caenorhabditis elegans as a model animal. Four suitable molecular descriptors were selected on the basis of genetic function approximation algorithm to construct a QSAR model with an R^2 value of 0.938. The predicted lgLC50 in this work are in agreement with the experimental values, indicating that the model has good stability and predictive ability. Our study provides a valuable model to predict the potential toxicity of ILs with different sub-structures to the environment and human health.展开更多
Diabetes mellitus(DM)is a common multifactorial disease,causing various complications,such as chronic metabolism.The current therapies for diabetes mellitus are commercial diabetic drugs that have different definite s...Diabetes mellitus(DM)is a common multifactorial disease,causing various complications,such as chronic metabolism.The current therapies for diabetes mellitus are commercial diabetic drugs that have different definite side effect.However,polysaccharides mainly extracted from natural resources,have advantages of safety,accessibility,and anti-diabetic potential.We have summarized recent research of natural polysaccharides with hypoglycemic activities,focusing on different pharmacological mechanisms in various cell and animal models.The relationships of structure-hypoglycemic effect are also discussed in detail.This review could provide a comprehensive perspective for better understanding on development and mechanism of natural polysaccharides against diabetes mellitus,which have been required by clinical studies yet.展开更多
Quantitative structure-biodegradability relationships （QSBRs） were established to develop predictive models and mechanistic explanations for acid dyestuffs as well as biological activities. With a total of four desc...Quantitative structure-biodegradability relationships （QSBRs） were established to develop predictive models and mechanistic explanations for acid dyestuffs as well as biological activities. With a total of four descriptors, molecular weight （MW）, energies of the highest occupied molecular orbital （EHOMO）, the lowest unoccupied molecular orbital （ELUMO）, and the excited state （EES）, calculated using quantum chemical semi-empirical methodology, a series of models were analyzed between the dye biodegradability and each descriptor. Results showed that EHOMO and Mw were the dominant parameters controlling the biodegradability of acid dyes. A statistically robust QSBR model was developed for all studied dyes, with the combined application of EHOMO and Mw. The calculated biodegradations fitted well with the experimental data monitored in a facultative-aerobic process, indicative of the reliable prediction and mechanistic character of the developed model.展开更多
Fatty acids and derivatives(FADs)are resources for natural antimicrobials.In order to screen for additional potent antimicrobial agents,the antimicrobial activities of FADs against Staphylococcus aureus were examined ...Fatty acids and derivatives(FADs)are resources for natural antimicrobials.In order to screen for additional potent antimicrobial agents,the antimicrobial activities of FADs against Staphylococcus aureus were examined using a microplate assay.Monoglycerides of fatty acids were the most potent class of fatty acids,among which monotridecanoin possessed the most potent antimicrobial activity.The conventional quantitative structure-activity relationship(QSAR)and comparative molecular field analysis(CoMFA)were performed to establish two statistically reliable models(conventional QSAR:R2=0.942,Q 2 LOO=0.910;CoMFA:R 2=0.979,Q 2=0.588,respectively).Improved forecasting can be achieved by the combination of these two models that provide a good insight into the structureactivity relationships of the FADs and that may be useful to design new FADs as antimicrobial agents.展开更多
Breast cancer is presently one of the most common malignancies worldwide,with a higher fatality rate.In this study,a quantitative structure-activity relationship(QSAR)model of compound biological activity and ADMET(Ab...Breast cancer is presently one of the most common malignancies worldwide,with a higher fatality rate.In this study,a quantitative structure-activity relationship(QSAR)model of compound biological activity and ADMET(Absorption,Distribution,Metabolism,Excretion,Toxicity)properties prediction model were performed using estrogen receptor alpha(ERα)antagonist information collected from compound samples.We first utilized grey relation analysis(GRA)in conjunction with the random forest(RF)algorithm to identify the top 20 molecular descriptor variables that have the greatest influence on biological activity,and then we used Spearman correlation analysis to identify 16 independent variables.Second,a QSAR model of the compound were developed based on BP neural network(BPNN),genetic algorithm optimized BP neural network(GA-BPNN),and support vector regression(SVR).The BPNN,the SVR,and the logistic regression(LR)models were then used to identify and predict the ADMET properties of substances,with the prediction impacts of each model compared and assessed.The results reveal that a SVR model was used in QSAR quantitative prediction,and in the classification prediction of ADMET properties:the SVR model predicts the Caco-2 and hERG(human Ether-a-go-go Related Gene)properties,the LR model predicts the cytochrome P450 enzyme 3A4 subtype(CYP3A4)and Micronucleus(MN)properties,and the BPNN model predicts the Human Oral Bioavailability(HOB)properties.Finally,information entropy theory is used to validate the rationality of variable screening,and sensitivity analysis of the model demonstrates that the constructed model has high accuracy and stability,which can be used as a reference for screening probable active compounds and drug discovery.展开更多
Echinops latifolius Tausch(ELT)is the traditional Mongolian medicine for the treatment of osteoporosis,and the ambiguous composition of active ingredients is an important factor in restricting the modernization and gl...Echinops latifolius Tausch(ELT)is the traditional Mongolian medicine for the treatment of osteoporosis,and the ambiguous composition of active ingredients is an important factor in restricting the modernization and globalization of this herb.Considering the traditional activity screening strategy is time-consuming and labor intensive,online HPLC active ingredient detection coupled with ESI-IT-TOF-MS^(n) strategy was employed in this study to isolate,identify and screen active compounds from the herbal medicines at the same time.The structure-activity relationship of these compounds was elucidated as well.Owing to the association of osteoporosis progression and oxidative stress,the antioxidants screening from ELT could be a good interpretive of the active substance in this herb.Meanwhile,DPPH equivalent method was an indicative of the most powerful antioxidant in ELT.Consequently,the screening and identification of the antioxidants in ELT was performed by using on-line HPLC-radical scavenging detection coupled with ESI-IT-TOF-MS^(n) strategy,and the structure-activity relationship was investigated based on DPPH equivalent method.Finally,20 constituents(including apigenin glucosides,caffeic acid,biscaffeoylquinic acids,biscaffeoylquinic acid methyl esters,ect.)were characterized in ELT extracts,and 18 components showed appreciable radical scavenging capacity.In addition,the structure-activity relationship study was carried out based on 14 compounds isolated from our laboratory,and the structural requirements of the compounds on antioxidant activity were obtained:(1)compounds with phenolic hydroxyl groups could have antioxidant activity;(2)the antioxidant activity could not be facilitated by the number of hydroxyl groups,but affected by the number of caffeoyl groups;(3)the substitution position of caffeoyl on quinic acid had a greater influence on DPPH activity;(4)methoxy groups could reduce the antioxidant activity.Collectively,this work provided the biochemical perspective to link active compounds and anti-osteoporosis action of ELT,and further explained how ELT worked in osteoporosis patients with bone loss.展开更多
Fentanyl is a potent and widely used clinical narcotic analgesic, as well as a highly selective IJ-opioid agonist. The present study established a homologous model of the human μ-opioid receptor; an intercomparison o...Fentanyl is a potent and widely used clinical narcotic analgesic, as well as a highly selective IJ-opioid agonist. The present study established a homologous model of the human μ-opioid receptor; an intercomparison of three types of μ-opioid receptor protein sequence homologous rates was made. The secondary receptor structure was predicted, the model reliability was assessed and verified using the Ramachandran plot and ProTab analysis. The predictive ability of the CoMFA model was further validated using an external test set. Using the Surflex-Dock program, a series of fentanyl analog molecules were docked to the receptor, the calculation results from Biopolymer/SitelD showed that the receptor had a deep binding area situated in the extracellular side of the transmembrane domains （TM） among TM3, TM5, TM6, and TMT. Results suggested that there might be 5 active areas in the receptor. The important residues were Asp147, Tyr148, and Tyr149 in TM3, Trp293, and His297 in TM6, and Trp318, His319, Ile322, and Tyr326 in TM7, which were located at the 5 active areas. The best fentanyl docking orientation position was the piperidine ring, which was nearly perpendicular to the membrane surface in the 7 TM domains. Molecular dynamic simulations were applied to evaluate potential relationships between ligand conformation and fentanyl substitution.展开更多
A new set of descriptors, HSEHPCSV （component score vector of hydrophobic, steric, and electronic properties together with hydrogen bonding contributions）, were derived from principal component analyses of 95 physic...A new set of descriptors, HSEHPCSV （component score vector of hydrophobic, steric, and electronic properties together with hydrogen bonding contributions）, were derived from principal component analyses of 95 physicochemical variables of 20 natural amino acids separately according to different kinds of properties described, namely, hydrophobic, steric, and electronic properties as well as hydrogen bonding contributions. HSEHPCSV scales were then employed to express structures of angiotensin-converting enzyme inhibitors, bitter tasting thresholds and bactericidal 18 peptide, and to construct QSAR models based on partial least square （PLS）. The results obtained are as follows： the multiple correlation coefficient （R2cum） of 0.846, 0.917 and 0.993, leave-one-out cross validated Q2cm of 0.835, 0.865 and 0.899, and root-mean-square error for estimated error （RMSEE） of 0.396, 0.187and 0.22, respectively. Satisfactory results showed that, as new amino acid scales, data of HSEHPCSV may be a useful structural expression methodology＇for the studies on peptide QSAR （quantitative structure-activity relationship） due to many advantages such as plentiful structural information, definite physical and chemical meaning and easy interpretation.展开更多
With the artificial neural network（ANN） method combined with the multiple linear regression（MLR）,based on a series of quantum chemical descriptors and molecular connectivity indexes,quantitative structure-activity...With the artificial neural network（ANN） method combined with the multiple linear regression（MLR）,based on a series of quantum chemical descriptors and molecular connectivity indexes,quantitative structure-activity relationship（QSAR） models to predict the acute toxicity（-lgEC50） of substituted aromatic compounds to Photobacterium phosphoreum were established.Four molecular descriptors that appear in the MLR model,namely,the second order valence molecular connectivity index（2XV）,the energy of the highest occupied molecular orbital（EHOMO）,the logarithm of n-octyl alcohol/water partition coefficient（logKow） and the Connolly molecular area（MA）,were inputs of the ANN model.The root-mean-square error（RMSE） of the training and validation sets of the ANN model are 0.1359 and 0.2523,and the correlation coefficient（R） is 0.9810 and 0.8681,respectively.The leave-one-out（LOO） cross validated correlation coefficient（Q L2OO） of the MLR and ANN models is 0.6954 and 0.6708,respectively.The result showed that the two methods are complementary in the calculations.The regression method gave support to the neural network with physical explanation,and the neural network method gave a more accurate model for QSAR.In addition,some insights into the structural factors affecting the acute toxicity and toxicity mechanism of substituted aromatic compounds were discussed.展开更多
Carotenoids are a family of effective active oxygen scavengers, which can reduce the danger of occurrence of chronic diseases such as cardiovascular disease, cataract, cancer, and so on. The quantitative structure-act...Carotenoids are a family of effective active oxygen scavengers, which can reduce the danger of occurrence of chronic diseases such as cardiovascular disease, cataract, cancer, and so on. The quantitative structure-activity relationship （QSAR） equation between carotenoids and antioxidant activity was established by quantum chemistry AM1, molecular mechanism （MM＋） and stepwise regression analysis methods, and the model was evaluated by leave-one-out approach. The results showed that the significant molecular descriptors related to the antioxidant activity of carotenoids were the energy difference （E_HL） between the lowest unoccupied molecular orbital （LUMO） and the highest occupied molecular orbital （HOMO） and ionization energy （Eiso）. The model showed a good predictive ability （Q^2 〉 0.5）.展开更多
To study structure-activity relationship of rhodomyrtone against Gram-positive bacteria, structural modification of rhodo- myrtone was carded out to afford its 10 analogues. All compounds were assayed for their antiba...To study structure-activity relationship of rhodomyrtone against Gram-positive bacteria, structural modification of rhodo- myrtone was carded out to afford its 10 analogues. All compounds were assayed for their antibacterial potency using broth microdilution method. The results indicated that rhodomyrtone exhibited higher antibacterial activity against al! Gram-positive bacteria than its analogues, with the exception of rhodomyrtone 6,8-diacetate （3） and oxime analogues 6 and 7 which demonstrated similar activity as the parent compound against Bacillus subtilis and Staphylococcus epidermidis with minimum inhibitory concentration and minimum bactericidal concentration ranged from 1 to 4 ~g/mL and 2 to 4 ~g/mL, respectively. In contrast, all analogues displayed no activity against Acinetobacter baumannii. Hydroxyl and ketone groups of rhodomyrtone were elucidated to be essential for the antibacterial property.展开更多
Aerogels are special porous materials with low thermal conductivity,light weight,high energy absorption rate and large surface area,which have been applied in many fields.However,controlling the aerogel microstructure...Aerogels are special porous materials with low thermal conductivity,light weight,high energy absorption rate and large surface area,which have been applied in many fields.However,controlling the aerogel microstructure remains an academic challenge.Herein,by employing graphene oxide(GO)as the aerogel skeleton and utilizing poly(vinyl alcohol)(PVA)to regulate the ice crystal growth,we elucidate the relationships between the physicochemical properties of GO/PVA aerogel precursors and the nucleation and growth of ice crystals by using an ice-templating method.We demonstrate that due to the hydrogen bond formed between PVA and water molecules,resulting in the initial crystallization temperature being reduced from-12.60℃(GO/PVA-0.01)to-16.21℃(GO/PVA-0.1).Meanwhile,the strong hydrogen bond between PVA and GO limits the diffusion of water molecules,thereby inhibiting the growth of ice crystals,decreasing the pore size of the GO/PVA aerogel from 9.96 nm(GO/PVA-0.01)to 7.19 nm(GO/PVA-0.3),and thus the compressive strength of the aerogel increases from 0.045 MPa to 0.13MPa.Overall,the finding of this study can be extended to other aerogel precursors,and exhibit important scientific value and practical significance for the preparation of aerogel materials with highly controllable structures and performances.展开更多
The antioxidant and gap junctional communication（GJC） activities of carotenoids are known to be the two main anticancer mechanisms.Quantitative structure-activity relationship（QSAR） models of the two activities we...The antioxidant and gap junctional communication（GJC） activities of carotenoids are known to be the two main anticancer mechanisms.Quantitative structure-activity relationship（QSAR） models of the two activities were developed using stepwise regression and multilayer perceptron neural network based on the calculated descriptors of quantum chemistry.The results showed that the significant molecular descriptor related to the antioxidant activity of carotenoids was the HOMO-LUMO energy gap（EHL） and the molecular descriptor related to the GJC was the lowest unoccupied molecular orbital energy（ELUMO）.The two models of antioxidant activity both showed good predictive power,but the predictive power of the neural network QSAR model of antioxidant activity was better.In addition,the two GJC models have similar,moderate predictive power.The possible mechanisms of antioxidant activity and GJC of carotenoids were discussed.展开更多
Gout is caused by the deposition of uric acid as monosodium urate（MSU）. Chronic hyperuricemia is the necessary condition for MSU deposition, which arises from over-production and/or under-excretion of uric acid. Ren...Gout is caused by the deposition of uric acid as monosodium urate（MSU）. Chronic hyperuricemia is the necessary condition for MSU deposition, which arises from over-production and/or under-excretion of uric acid. Renal under-excretion of uric acid accounts for greater than 90% of the patients with hyperuricemia, making URAT1 inhibitors, which act through uricosuric effect a promising class of urate-lowering therapy（ULT）. This review aims at the summary and discussion of the latest development of URAT1 inhibitors for the treatment of hyperuricemia and gout and providing an insight into their structure-activity relationship（SAR）, which will be helpful to the design of URAT1 inhibitors for both academic research and pharmaceutical industry. The current development pipeline of URAT1 inhibitors is promising and encouraging.展开更多
基金the National Natural Science Foundation of China(No.52000093)Yunnan Fundamental Research Projects(No.202101BE070001-001)National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2019B03).
文摘NH_(3) in ambient air directly leads to an increase in the aerosol content in the air. These substances lead to the formation of haze to various environmental problems after atmospheric circulation and diffusion. Controlling NH_(3) emissions caused by ammonia escaping from mobile and industrial sources can effectively reduce the NH_(3) content in ambient air. Among the various NH_(3) removal methods, the selective catalytic oxygen method (NH_(3)-SCO) is committed to oxidizing NH_(3) to environmentally harmless H_(2)O and N_(2);therefore, it is the most valuable and ideal ammonia removal method. In this review, the characteristics of loaded and core-shell catalysts in NH_(3)-SCO have been reviewed in the context of catalyst structure-activity relationships, and the H_(2)O resistance and SO2 resistance of the catalysts are discussed in the context of practical application conditions. Then the effects of the valence state of the active center, oxygen species on the catalyst surface, dispersion of the active center and acidic sites on the catalyst performance are discussed comprehensively. Finally, the shortcomings of the existing catalysts are summarized and the catalyst development is discussed based on the existing studies.
基金the funding support from the National Key Research and Development Program of China(2019YFE0123400)the Tianjin Distinguished Young Scholars Fund(20JCJQJC00260)+4 种基金the Major Science and Technology Project of Anhui Province(202203f07020007)the Anhui Conch Group Co.,Ltdthe“111”Project(B16027)the funding support from the Natural Science Foundation of China(22209081)the fellowship of China Postdoctoral Science Foundation(2021M690082)。
文摘Developing bimetallic catalysts is an effective strategy for enhancing the activity and selectivity of electrochemical CO_(2) reduction reactions,where understanding the structure-activity relationship is essential for catalyst design.Herein,we prepared two Cu-Ag bimetallic catalysts with Ag nanoparticles attached to the top or the bottom of Cu nanowires.When tested in a flow cell,the Cu-Ag catalyst with Ag nanoparticles on the bottom achieved a faradaic efficiency of 54%for ethylene production,much higher than the catalyst with Ag nanoparticles on the top.The catalysts were further studied in the H-cell and zero-gap MEA cell.It was found that placing the two metals in the intensified reaction zone is crucial to triggering the tandem reaction of bimetallic catalysts.Our work elucidates the structure-activity relationship of bimetallic catalysts for CO_(2) reduction and demonstrates the importance of considering both catalyst structures and cell characteristics to achieve high activity and selectivity.
基金This work was supported by National Nature Science Foundation of China and China Academy of Engineering Physics （No. 10376021） Provincial National Science Foundation of He＇nan （No. 2004601107）.
文摘Density functional theory （DFT） was used to calculate molecular descriptors （properties） for 12 fluoro-quinolone with anti-S.pneumoniae activity. Principal component analysis （PCA） and hierarchical cluster analysis （HCA） were employed to reduce dimensionality and investigate in which variables should be more effective for classifying fluoroquinolones according to their degree of an-S.pneumoniae activity. The PCA results showed that the variables ELUMO, Q3, Q5, QA, logP, MR, VOL and △EHL of these compounds were responsible for the anti-S.pneumoniae activity. The HCA results were similar to those obtained with PCA.The methodologies of PCA and HCA provide a reliable rule for classifying new fluoroquinolones with antiS.pneumoniae activity. By using the chemometric results, 6 synthetic compounds were analyzed through the PCA and HCA and two of them are proposed as active molecules with anti-S.pneumoniae, which is consistent with the results of clinic experiments.
基金Supported by the National Natural Science Foundation of China(31060045,31260091)~~
文摘Taking the six common anthocyanidins in nature, i.e. cyanidin, delphinidin, malvidin, pelargonidin, peonidin and petunidin, as examples, this paper summarized the main achievements about the structure-activity relationships of the coloration and stability of anthocyanidins. The coloration and stability of anthocyanidins are funda- mentally determined by the chemical and spatial structures of the anthocyanidins. The electron-deficient state, hydroxylation and methylation patterns, especially the ones on the B-ring, and coplanarity of the three rings of anthocyanidins are inde- pendently or synergetically, positively and/or negatively, influence the coloration and stability of the anthocyanidins. Thereinto, the in vivo colorations of anthocyanins are also related to the organ-selective and crystal- or anthocyanic vacuolar inclusion- related existence of the anthocyanidins. This review could provide a reference for the researches of the structure-optimizing and function-exploiting of anthocyanidins and also for the selection of the crops and cultivars containing specific anthocyani- din profiles.
基金the National Natural Science Foundation of China(No.32272575)National College Student Innovation and Entrepreneurship Training Program(No.202210459164)for financial support.
文摘Methicillin-resistant Staphylococcus aureus (MRSA), the most common pathogen in hospital and community environments, can cause serious and even fatal infections. The antibiotics currently used for clinical treatment of MRSA have developed resistance, and there is an urgent need to develop new antimicrobials to treat infections caused by MRSA strains. Quinoline analogues play an important role in the development of antimicrobials. Herein, we discussed the current development of antibacterial activities of quinoline analogues, mainly for anti-MRSA activity, and their structure-activity relationships (SARs) from the perspective of using the quinoline nucleus to search for novel potential anti-MRSA candidates. Additionally, the mechanisms of some representative quinoline analogues against MRSA were clarified. Altogether, this review could provide further insights for the rational development of quinoline-based antibacterial drugs, especially against MRSA.
文摘In searching for effective anticonvulsant agents,fourteen 6-aryl-4.5-di- hydro-3(2H)pyridazinones.fifteen 6-aryl-3(2H)pyridazinones,and seventeen 3-GABA derivatives of 6-aryIpyridazines have been synthesized,and evaluated in mice for the ability to antagonize maximal electroshock seizure(MES).The ED_(50) values showed that 6-(2′,4′- dichlorophenyt)-3(2H)pyridazinone was the most potent anticonvulsant among these corn- pounds(ED_(50)=10.15 mg/kg).The structure-activity relationships of the aryl pyridazinones were studied.The result showed that:(1)the higher the value of the hydrophobic parameter л of the substituent on the phenyl ring.the more potent the anticonvulsant activity of the corn- pound.and(2)only the compounds with an electron withdrawing substituent on the phenyl ring exhibited appreciable anticonvulsant activity.
基金This work was supported by the National Natural Science Foundation of China （No.21477121）, and the Fundamental Research Funds for the Central Universities for the support of this work. The numerical calculations were performed on the super computing system in the Supercomputing Center at the University of Science and Technology of China.
文摘Due to the large number of ionic liquids （ILs） and their potential environmental risk, assessing the toxicity of ILs by ecotoxicological experiment only is insufficient. Quantitative structure- activity relationship （QSAR） has been proven to be a quick and effective method to estimate the viscosity, melting points, and even toxicity of ILs. In this work, the LC50 values of 30 imidazolium-based ILs were determined with Caenorhabditis elegans as a model animal. Four suitable molecular descriptors were selected on the basis of genetic function approximation algorithm to construct a QSAR model with an R^2 value of 0.938. The predicted lgLC50 in this work are in agreement with the experimental values, indicating that the model has good stability and predictive ability. Our study provides a valuable model to predict the potential toxicity of ILs with different sub-structures to the environment and human health.
基金financially supported by the National Natural Science Foundation of China(32201969)Natural Science Foundation of Henan Province(212300410297)+3 种基金Basic Research Plan of Higher Education School Key Scientific Research Project of Henan Province(21A550014)Doctoral Research Foundation of Zhengzhou University of Light Industry(2020BSJJ015)Program for Science and Technology Innovation Talents in Universities of Henan Province(20HASTIT037)Youth Talents Project of Henan Province(2020HYTP046).
文摘Diabetes mellitus(DM)is a common multifactorial disease,causing various complications,such as chronic metabolism.The current therapies for diabetes mellitus are commercial diabetic drugs that have different definite side effect.However,polysaccharides mainly extracted from natural resources,have advantages of safety,accessibility,and anti-diabetic potential.We have summarized recent research of natural polysaccharides with hypoglycemic activities,focusing on different pharmacological mechanisms in various cell and animal models.The relationships of structure-hypoglycemic effect are also discussed in detail.This review could provide a comprehensive perspective for better understanding on development and mechanism of natural polysaccharides against diabetes mellitus,which have been required by clinical studies yet.
基金Project supported by the Natural Science Foundation of Shanghai, China(No. 06ZR14002).
文摘Quantitative structure-biodegradability relationships （QSBRs） were established to develop predictive models and mechanistic explanations for acid dyestuffs as well as biological activities. With a total of four descriptors, molecular weight （MW）, energies of the highest occupied molecular orbital （EHOMO）, the lowest unoccupied molecular orbital （ELUMO）, and the excited state （EES）, calculated using quantum chemical semi-empirical methodology, a series of models were analyzed between the dye biodegradability and each descriptor. Results showed that EHOMO and Mw were the dominant parameters controlling the biodegradability of acid dyes. A statistically robust QSBR model was developed for all studied dyes, with the combined application of EHOMO and Mw. The calculated biodegradations fitted well with the experimental data monitored in a facultative-aerobic process, indicative of the reliable prediction and mechanistic character of the developed model.
基金Project(No.31071501)supported by the National Natural Science Foundation of China
文摘Fatty acids and derivatives(FADs)are resources for natural antimicrobials.In order to screen for additional potent antimicrobial agents,the antimicrobial activities of FADs against Staphylococcus aureus were examined using a microplate assay.Monoglycerides of fatty acids were the most potent class of fatty acids,among which monotridecanoin possessed the most potent antimicrobial activity.The conventional quantitative structure-activity relationship(QSAR)and comparative molecular field analysis(CoMFA)were performed to establish two statistically reliable models(conventional QSAR:R2=0.942,Q 2 LOO=0.910;CoMFA:R 2=0.979,Q 2=0.588,respectively).Improved forecasting can be achieved by the combination of these two models that provide a good insight into the structureactivity relationships of the FADs and that may be useful to design new FADs as antimicrobial agents.
基金Supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_0082)
文摘Breast cancer is presently one of the most common malignancies worldwide,with a higher fatality rate.In this study,a quantitative structure-activity relationship(QSAR)model of compound biological activity and ADMET(Absorption,Distribution,Metabolism,Excretion,Toxicity)properties prediction model were performed using estrogen receptor alpha(ERα)antagonist information collected from compound samples.We first utilized grey relation analysis(GRA)in conjunction with the random forest(RF)algorithm to identify the top 20 molecular descriptor variables that have the greatest influence on biological activity,and then we used Spearman correlation analysis to identify 16 independent variables.Second,a QSAR model of the compound were developed based on BP neural network(BPNN),genetic algorithm optimized BP neural network(GA-BPNN),and support vector regression(SVR).The BPNN,the SVR,and the logistic regression(LR)models were then used to identify and predict the ADMET properties of substances,with the prediction impacts of each model compared and assessed.The results reveal that a SVR model was used in QSAR quantitative prediction,and in the classification prediction of ADMET properties:the SVR model predicts the Caco-2 and hERG(human Ether-a-go-go Related Gene)properties,the LR model predicts the cytochrome P450 enzyme 3A4 subtype(CYP3A4)and Micronucleus(MN)properties,and the BPNN model predicts the Human Oral Bioavailability(HOB)properties.Finally,information entropy theory is used to validate the rationality of variable screening,and sensitivity analysis of the model demonstrates that the constructed model has high accuracy and stability,which can be used as a reference for screening probable active compounds and drug discovery.
基金National Natural Science Foundation of China(Grant No.81860756,81960758)Natural Science Foundation of Inner Mongolia Autonomous Region(Grant No.2017MS08122,2019MS08111 and 2019MS08119)+2 种基金Inner Mongolia Science and Technology Innovation Guide Project(Grant No.02039001)Rolling Support Plan for Grassland Talents Project in Inner Mongolia Autonomous RegionInner Mongolia Autonomous Region Higher Education Science Research Project(Grant No.NJZY19099)。
文摘Echinops latifolius Tausch(ELT)is the traditional Mongolian medicine for the treatment of osteoporosis,and the ambiguous composition of active ingredients is an important factor in restricting the modernization and globalization of this herb.Considering the traditional activity screening strategy is time-consuming and labor intensive,online HPLC active ingredient detection coupled with ESI-IT-TOF-MS^(n) strategy was employed in this study to isolate,identify and screen active compounds from the herbal medicines at the same time.The structure-activity relationship of these compounds was elucidated as well.Owing to the association of osteoporosis progression and oxidative stress,the antioxidants screening from ELT could be a good interpretive of the active substance in this herb.Meanwhile,DPPH equivalent method was an indicative of the most powerful antioxidant in ELT.Consequently,the screening and identification of the antioxidants in ELT was performed by using on-line HPLC-radical scavenging detection coupled with ESI-IT-TOF-MS^(n) strategy,and the structure-activity relationship was investigated based on DPPH equivalent method.Finally,20 constituents(including apigenin glucosides,caffeic acid,biscaffeoylquinic acids,biscaffeoylquinic acid methyl esters,ect.)were characterized in ELT extracts,and 18 components showed appreciable radical scavenging capacity.In addition,the structure-activity relationship study was carried out based on 14 compounds isolated from our laboratory,and the structural requirements of the compounds on antioxidant activity were obtained:(1)compounds with phenolic hydroxyl groups could have antioxidant activity;(2)the antioxidant activity could not be facilitated by the number of hydroxyl groups,but affected by the number of caffeoyl groups;(3)the substitution position of caffeoyl on quinic acid had a greater influence on DPPH activity;(4)methoxy groups could reduce the antioxidant activity.Collectively,this work provided the biochemical perspective to link active compounds and anti-osteoporosis action of ELT,and further explained how ELT worked in osteoporosis patients with bone loss.
基金supported by the National Natural Science Foundation of China(Molecular design,catalysis and synthesis methods of novel fentanyl analogs active compounds)No.20872095
文摘Fentanyl is a potent and widely used clinical narcotic analgesic, as well as a highly selective IJ-opioid agonist. The present study established a homologous model of the human μ-opioid receptor; an intercomparison of three types of μ-opioid receptor protein sequence homologous rates was made. The secondary receptor structure was predicted, the model reliability was assessed and verified using the Ramachandran plot and ProTab analysis. The predictive ability of the CoMFA model was further validated using an external test set. Using the Surflex-Dock program, a series of fentanyl analog molecules were docked to the receptor, the calculation results from Biopolymer/SitelD showed that the receptor had a deep binding area situated in the extracellular side of the transmembrane domains （TM） among TM3, TM5, TM6, and TMT. Results suggested that there might be 5 active areas in the receptor. The important residues were Asp147, Tyr148, and Tyr149 in TM3, Trp293, and His297 in TM6, and Trp318, His319, Ile322, and Tyr326 in TM7, which were located at the 5 active areas. The best fentanyl docking orientation position was the piperidine ring, which was nearly perpendicular to the membrane surface in the 7 TM domains. Molecular dynamic simulations were applied to evaluate potential relationships between ligand conformation and fentanyl substitution.
基金Supported by the National High Technology Research and Development Program of China (863 Program, No. 2006AA02Z312)
文摘A new set of descriptors, HSEHPCSV （component score vector of hydrophobic, steric, and electronic properties together with hydrogen bonding contributions）, were derived from principal component analyses of 95 physicochemical variables of 20 natural amino acids separately according to different kinds of properties described, namely, hydrophobic, steric, and electronic properties as well as hydrogen bonding contributions. HSEHPCSV scales were then employed to express structures of angiotensin-converting enzyme inhibitors, bitter tasting thresholds and bactericidal 18 peptide, and to construct QSAR models based on partial least square （PLS）. The results obtained are as follows： the multiple correlation coefficient （R2cum） of 0.846, 0.917 and 0.993, leave-one-out cross validated Q2cm of 0.835, 0.865 and 0.899, and root-mean-square error for estimated error （RMSEE） of 0.396, 0.187and 0.22, respectively. Satisfactory results showed that, as new amino acid scales, data of HSEHPCSV may be a useful structural expression methodology＇for the studies on peptide QSAR （quantitative structure-activity relationship） due to many advantages such as plentiful structural information, definite physical and chemical meaning and easy interpretation.
基金supported by the Natural Science Foundation of Fujian Province (D0710019)the Natural Science Foundation of Overseas Chinese Affairs Office of the State Council (06QZR09)
文摘With the artificial neural network（ANN） method combined with the multiple linear regression（MLR）,based on a series of quantum chemical descriptors and molecular connectivity indexes,quantitative structure-activity relationship（QSAR） models to predict the acute toxicity（-lgEC50） of substituted aromatic compounds to Photobacterium phosphoreum were established.Four molecular descriptors that appear in the MLR model,namely,the second order valence molecular connectivity index（2XV）,the energy of the highest occupied molecular orbital（EHOMO）,the logarithm of n-octyl alcohol/water partition coefficient（logKow） and the Connolly molecular area（MA）,were inputs of the ANN model.The root-mean-square error（RMSE） of the training and validation sets of the ANN model are 0.1359 and 0.2523,and the correlation coefficient（R） is 0.9810 and 0.8681,respectively.The leave-one-out（LOO） cross validated correlation coefficient（Q L2OO） of the MLR and ANN models is 0.6954 and 0.6708,respectively.The result showed that the two methods are complementary in the calculations.The regression method gave support to the neural network with physical explanation,and the neural network method gave a more accurate model for QSAR.In addition,some insights into the structural factors affecting the acute toxicity and toxicity mechanism of substituted aromatic compounds were discussed.
基金Supported by the Chinese National Key Technologies R & D Program of 11th Five-year Plan (2006BAD27B06)Education Foundation of Innovative Engineering Key Project of Education Department (707034)
文摘Carotenoids are a family of effective active oxygen scavengers, which can reduce the danger of occurrence of chronic diseases such as cardiovascular disease, cataract, cancer, and so on. The quantitative structure-activity relationship （QSAR） equation between carotenoids and antioxidant activity was established by quantum chemistry AM1, molecular mechanism （MM＋） and stepwise regression analysis methods, and the model was evaluated by leave-one-out approach. The results showed that the significant molecular descriptors related to the antioxidant activity of carotenoids were the energy difference （E_HL） between the lowest unoccupied molecular orbital （LUMO） and the highest occupied molecular orbital （HOMO） and ionization energy （Eiso）. The model showed a good predictive ability （Q^2 〉 0.5）.
基金the Royal Golden Jubilee Ph.D. Program(No.PHD/0023/255 1),Prince of Songkla Universitythe National Research University Project of Thailand's Office ofthe Higher Education Commission for financial supportSupport from the Center of Excellence for Innovation in Chemistry is gratefully acknowledged
文摘To study structure-activity relationship of rhodomyrtone against Gram-positive bacteria, structural modification of rhodo- myrtone was carded out to afford its 10 analogues. All compounds were assayed for their antibacterial potency using broth microdilution method. The results indicated that rhodomyrtone exhibited higher antibacterial activity against al! Gram-positive bacteria than its analogues, with the exception of rhodomyrtone 6,8-diacetate （3） and oxime analogues 6 and 7 which demonstrated similar activity as the parent compound against Bacillus subtilis and Staphylococcus epidermidis with minimum inhibitory concentration and minimum bactericidal concentration ranged from 1 to 4 ~g/mL and 2 to 4 ~g/mL, respectively. In contrast, all analogues displayed no activity against Acinetobacter baumannii. Hydroxyl and ketone groups of rhodomyrtone were elucidated to be essential for the antibacterial property.
基金financially supported by the National Natural Science Foundation of China(No.51873133)。
文摘Aerogels are special porous materials with low thermal conductivity,light weight,high energy absorption rate and large surface area,which have been applied in many fields.However,controlling the aerogel microstructure remains an academic challenge.Herein,by employing graphene oxide(GO)as the aerogel skeleton and utilizing poly(vinyl alcohol)(PVA)to regulate the ice crystal growth,we elucidate the relationships between the physicochemical properties of GO/PVA aerogel precursors and the nucleation and growth of ice crystals by using an ice-templating method.We demonstrate that due to the hydrogen bond formed between PVA and water molecules,resulting in the initial crystallization temperature being reduced from-12.60℃(GO/PVA-0.01)to-16.21℃(GO/PVA-0.1).Meanwhile,the strong hydrogen bond between PVA and GO limits the diffusion of water molecules,thereby inhibiting the growth of ice crystals,decreasing the pore size of the GO/PVA aerogel from 9.96 nm(GO/PVA-0.01)to 7.19 nm(GO/PVA-0.3),and thus the compressive strength of the aerogel increases from 0.045 MPa to 0.13MPa.Overall,the finding of this study can be extended to other aerogel precursors,and exhibit important scientific value and practical significance for the preparation of aerogel materials with highly controllable structures and performances.
基金Supported by the Chinese National Key Technologies R&D Program of 11th Five-year Plan (2006BAD27B06)the Fundamental Research Funds for the Central Universities and Education Foundation of Innovative Engineering Key Project of Education Department (707034)
文摘The antioxidant and gap junctional communication（GJC） activities of carotenoids are known to be the two main anticancer mechanisms.Quantitative structure-activity relationship（QSAR） models of the two activities were developed using stepwise regression and multilayer perceptron neural network based on the calculated descriptors of quantum chemistry.The results showed that the significant molecular descriptor related to the antioxidant activity of carotenoids was the HOMO-LUMO energy gap（EHL） and the molecular descriptor related to the GJC was the lowest unoccupied molecular orbital energy（ELUMO）.The two models of antioxidant activity both showed good predictive power,but the predictive power of the neural network QSAR model of antioxidant activity was better.In addition,the two GJC models have similar,moderate predictive power.The possible mechanisms of antioxidant activity and GJC of carotenoids were discussed.
基金Supported by Key Projects of Tianjin Science and Technology Support Plan(16YFZCSY00910)Natural Science Foundation of Shandong Province(ZR2015BM028)
文摘Gout is caused by the deposition of uric acid as monosodium urate（MSU）. Chronic hyperuricemia is the necessary condition for MSU deposition, which arises from over-production and/or under-excretion of uric acid. Renal under-excretion of uric acid accounts for greater than 90% of the patients with hyperuricemia, making URAT1 inhibitors, which act through uricosuric effect a promising class of urate-lowering therapy（ULT）. This review aims at the summary and discussion of the latest development of URAT1 inhibitors for the treatment of hyperuricemia and gout and providing an insight into their structure-activity relationship（SAR）, which will be helpful to the design of URAT1 inhibitors for both academic research and pharmaceutical industry. The current development pipeline of URAT1 inhibitors is promising and encouraging.
